The Priory of Finchelsea XVIII

Sir Richard Arcos listened to the story with patience, and finally burst out laughing as Lil completed it.
"That, lass, has to be a classic, even for you! So you're left with a key that opens we-know-not-what, and a police dragnet out for you. Kathy, can you shed any light on the situation?"
Kathy looked guilty, and Lil's large blue eyes met hers.
"Kathy, there's something you're not telling us," Lil said, a tone of reproach in her voice.
"Well... it's painful." Kathy told her.
"I know it is. But you're not the one who's suspected of a bizarre murder I couldn't have committed. I wish you were..."
"I know you couldn't have killed Dr. Llewellyn Pryce-Rees-Evans-Jones, because he was fascinated by the legend of the Holy Grail and a lot of things that you just rubbish in your books."
"The Holy Grail," Sir Richard said soberly, "is in a bank vault in Aberystwyth, and you will never know what difficulties and tribulations Dr. Barton and myself suffered to keep it there. But I interrupt."
"Just a second," Lil said suspiciously, "you knew Dr. Llewellyn Pryce-Rees-Evans-Jones?"
"I knew him very well, Dr. Barton. You see, Dr. Llewellyn Pryce-Rees-Evans-Jones was my uncle."
Lil groaned at the news.